Contactless Radiofrequency Identification Devices (RFIDs) are increasingly used for identification of persons moving about in controlled access zones or transiting from one zone to another. A contactless RFID is a device made up of an antenna and a chip connected to the terminals of the antenna. The chip is usually not powered and receives its energy by an electromagnetic coupling between the antenna of the reader and the antenna of the RFID, information is exchanged between the RFID and the reader and particularly information stored in the chip that relates to the identification of the holder of the object on which the RFID is located and to his/her authorization to enter into a controlled access zone.
In this manner, passports can incorporate RFIDs to identify the passport holder. The chip memory contains information such as the identity of the passport holder, his/her country of origin, his/her nationality, visas of different countries visited, dates of entry, restrictions of movements, biometric elements, etc. The RFID device is generally incorporated into the bottom cover board of the passport. An antenna is then printed using ink loaded with conductive particles on the reinforced bottom cover board of the passport cover. The chip is then connected by gluing to the connection terminals of the antenna. Then, the flyleaf of the quire of passport pages is laminated to the back of the reinforced top cover board.
The RFID device can also be manufactured separately from the passport to be incorporated afterwards by gluing between the cover and the bottom flyleaf of the passport, for example. The RFID device featuring the antenna and the chip connected together is then integrated with a paper, plastic or other “inlay”.
RFID devices were also developed with an encased chip instead of a bare chip, commonly referred to as integrated circuit module. Recent developments to reduce the size of these modules have actually allowed their integration in passports without increasing the thickness or stiffness of the latter.
The problem of manufacturing a RFID device support integrating a module resides in the connection of the module to the antenna. Actually, traditional connections such as welding for example, used to connect the modules to the copper antennae are not applicable to printed antennas. The connection of the module to the antenna is made between the antenna contacts of the antenna support and the module contacts. Since this connection is made over a small surface, it must be reliable and solid. This connection is made by means of conductive glue in the case of an antenna composed of conductive ink. The making of such a connection requires the following manufacturing steps:
printing an antenna featuring contacts on a support,
depositing spots of conductive glue on antenna pads,
installing the electronic module on spots of conductive glue,
cross-linking of the conductive glue by passing through an oven.
Then, the traditional lamination step of various layers that make up the card is carried out by hot press molding, generally the lower and upper card body on either side of the antenna support.
Such a connection has drawbacks. When conductive glue is applied, short-circuits with the module could occur. Furthermore, spots of conductive glue that harden during cross-linking are likely to crack the contacts of the antenna under the pressure exerted during the lamination step or else during jerks and impacts exerted on the passport. The final risk then being the breakage of the electrical contact between the antenna and the integrated circuit module and thus permanent damage to the radiofrequency identification device.